1. Field of the Invention
The present invention relates generally to the transfer of data packets in a wireless telecommunications system, and more particularly to the routing of data packets between a data link connectable to the wireless telecommunications system and a subscriber terminal of the wireless telecommunications system.
2. Description of the Prior Art
In a typical wireless telecommunications system, a subscriber terminal may be located at a subscriber's premises for handling voice and data calls to and from that subscriber. One or more lines may be provided from the subscriber terminal for supporting one or more items of telecommunications equipment located at the subscriber's premises. Further, a central terminal may be provided for controlling a number of subscriber terminals, and in particular for managing calls between a subscriber terminal and other components of a wireless telecommunications network.
Each subscriber terminal communicates with the central terminal via a radio resource. In accordance with known techniques, multiple communication channels may be arranged to utilize the radio resource for the transmission of signals to and from the subscriber terminal. For example, in a “Code Division Multiple Access” (CDMA) system, a radio resource consisting of a particular frequency channel may be partitioned by applying different orthogonal codes to signals to be transmitted on that frequency channel. Signals to which an orthogonal code has been applied can be considered as being transmitted over a corresponding orthogonal communication channel utilizing the particular frequency channel. Similarly, in a “Time Division Multiple Access” (TDMA) system, a radio resource consisting of a particular frequency channel can be partitioned in the time domain, such that a number of different signals can be transmitted in different time slots, the time slots forming multiple communication channels utilizing the radio resource. As another example, in a “Frequency Division Multiple Access” (FDMA) system, a radio resource consisting of a band of frequencies may be partitioned to form a number of communication channels at particular frequencies, thereby enabling multiple signals to be transmitted over the radio resource.
Nowadays, there is an ever increasing demand for wireless telecommunications systems to be able to transmit data at higher and higher speeds, and this in turn requires the wireless telecommunications system to provide a wireless link with enough bandwidth to support such data transmissions. One way to transmit data is using a packet-based approach, where data is sent in discrete blocks (hereafter called “data packets”), and the communication channels are allocated as and when data packets are required to be sent (as contrasted with a typical voice call, where a communication channel is allocated for the duration of the call).
It is an object of the present invention to provide an efficient technique for transferring data packets in a wireless telecommunications system.